626. Colonization with Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae and Subsequent Risk of Bacteremia in Neutropenic Patients Undergoing Hematopoietic Stem Cell Transplantation
Session: Oral Abstract Session: Epidemiology of Transplant Infections
Thursday, October 8, 2015: 2:00 PM
Room: 25--ABC
Background: Bacteremia due to extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) is associated with inadequate empirical therapy and high mortality rates in neutropenic patients. Increased knowledge of ESBL-E colonization rates and risk of subsequent ESBL-E bacteremia in neutropenic populations are needed.

Methods: We collected perianal swabs from patients undergoing a hematopoietic stem cell transplant (HSCT) between December 2013-April 2015 on admission and weekly until neutrophil engraftment. Swabs were plated on HardyCHROM™ ESBL agar to detect ESBL-E colonization. Enterobacteriaceae isolated from swabs or blood cultures underwent testing for antimicrobial susceptibilities and β-lactamase genes. We determined the rate of ESBL-E colonization prior to HSCT and the risk of ESBL-E acquisition and bacteremia during neutropenia. Colonizing and bloodstream isolates from patients with ESBL-E bacteremia were genetically evaluated by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) typing.

Results: Ten percent of allogeneic (13/131) and 10% of autologous (8/80) HSCT recipients were colonized with ESBL-E on admission for transplant (Escherichia coli: 19; Klebsiella pneumoniae: 2). Susceptibility rates of ESBL-E to meropenem, piperacillin-tazobactam, cefepime and ceftazidime were 100%, 86%, 57% and 33%, respectively. BlaCTX-M was identified in 11 of 13 isolates that underwent genotyping (CTX-M-1: 9; CTX-M-9: 2). Of patients not initially colonized, 2.5% acquired ESBL-E during their transplant admission. ESBL-E bacteremia occurred during neutropenia in 6 of 13 (47%) allogeneic HSCT recipients who were colonized on admission, compared to 0 of 118 who were not colonized (P < 0.001). No autologous HSCT recipients developed ESBL-E bacteremia. Five pairs of colonizing and bloodstream isolates underwent molecular typing and all had identical MLST (ST 405: 3; ST 88, ST 648: 1) and PFGE patterns.

Conclusion: Allogeneic HSCT recipients who are colonized with ESBL-E have high rates of bacteremia from their colonizing strain during neutropenia. Assessing for pre-transplant ESBL-E colonization may identify neutropenic patients at high-risk for ESBL-E bacteremia who should receive a carbapenem as initial empirical therapy for new onset of fever.

Michael Satlin, MD, MS1, Kalyan Chavda, MS2, Stephen Jenkins, PhD3, Liang Chen, PhD2, Rosemary Soave, MD, FIDSA4, Catherine Small, MD4, Samantha Jacobs, MD4, Tsiporah Shore, MD5, Koen Van Besien, MD, PhD5, Audrey Schuetz, MD3, Thomas Walsh, MD, FIDSA4 and Barry N. Kreiswirth, PhD2, (1)New York-Presbyteria, New York, NY, (2)Public Health Research Institute, Rutgers New Jersey Medical School, Newark, NJ, (3)Pathology and Laboratory Medicine, Weill Cornell Medical College, New York, NY, (4)Internal Medicine/Infectious Diseases, Weill Cornell Medical College, New York, NY, (5)Internal Medicine/Hematology and Medical Oncology, Weill Cornell Medical College, New York, NY


M. Satlin, None

K. Chavda, None

S. Jenkins, None

L. Chen, None

R. Soave, None

C. Small, None

S. Jacobs, None

T. Shore, None

K. Van Besien, None

A. Schuetz, None

T. Walsh, None

B. N. Kreiswirth, None

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